Inflatable structure with braided layer

ABSTRACT

A balloon for medical treatments such as percutaneous transluminal coronary angioplasty (PTCA), delivery of a vascular stents or stent grafts, employs reinforcement materials that are patterned so as to promote consistent folding of the balloon. Also disclosed are methods and apparatus for biocidal treatment using a balloon, including balloons with fiber fabric reinforcements.

PRIORITY CLAIM AND INCORPORATION BY REFERENCE

This application is a continuation of U.S. Ser. No. 16/189,324, which isa continuation of U.S. Ser. No. 15/262,767, which is a continuation ofU.S. Ser. No. 12/444,796, which is a National Stage of PCT/US07/81264,which claims priority to U.S. Prov. 60/829,231.

TECHNICAL FIELD

The invention relates to composite structures for medical balloons andin particular, such structures that promote predictable folding.

BACKGROUND ART

Woven and braided fabrics have been used to reinforce various devices.Compared to weaving, braiding may impart greater strength for a unit ofweight. The strength of a braid comes from the fact that multiple yarnscan be intertwined without any being twisted around another. Generallythese are continuously braided at an angle and there is no need for anyyarn to suffer a sharp bend. As a result, loads may be distributedevenly and efficiently throughout the braid.

Automated fabrication of braids generally results in tubular or flatconfigurations. Braids can also be formed without any underlying support(freestanding) or over a mandrel or a part to be reinforced, such as themast of a sailboat. Braiding can also be done over a three-dimensionalpart, such as a tool.

A single braid can incorporate multiple yarn materials to form a hybridweave. This is often done to make patterns in the resulting product.Yarns can be of metal, carbon fiber, glass fiber, mono or multifilamentthreads, etc. Braiding can be done with very delicate materials.

Braid has been used as a reinforcement for some surgical devices such asendoscopes and catheters and for implantable devices such as splints andstents.

Non-woven fiber reinforcements are also known, for example, randomlyarrayed fibers such as in fiberglass and hand-laid fibers arrayed overand within a matrix are known strategies. Both have been described inconnection with the reinforcement of medical balloons.

Many composite balloon structures are reinforced by inelastic filaments,which is a good match for folding to minimize the collapsed balloon'svolume. However, the fiber can be an impediment to folding, an issuethat is addressed by at least some of the inventive embodimentsdisclosed below.

The following are some references to background in the field of braidingtechnology. A brief overview and comparison of 2D and 3D braidingmachines and the kinds of structures they can create is provided by anarticle, “Braiding,” 2005 Advanced Composite Materials & TextileResearch Laboratory, University of Massachusetts-Lowell. [online] August2007 [Retrieved on Jun. 21, 2006]. Retrieved from the Internet.<http://mechanical.uml.edu/acmtrl/research-Braiding.htm>.

The company, 3TEX, provides information about state of the artthree-dimensional automated braiding at [online] [Retrieved on Jun. 21,2005] Retrieved from the Internet <http://www.3tex.com/3braid.cfm>. Thepage shows photographs and an animation of a large Cartesian braidingmachine. One of the points made is that with computer control, it ispossible to shift the braiding pattern at any time without changing thenumber or continuity of the yarns.

A report by the National Textile Center (NTC) in Springhouse, Pa.discusses different kinds of braiding patterns such as diamond, regular,and Hercules braids and discusses behavior of braids under tensile load,the effect of yarn angle with respect to load and jamming condition, andother issues. “Engineered Non-Linear Elastic Blended Fabrics,” NTCProject F00-PH05 2005 [Retrieved on Jun. 21, 2006]. Retrieved from theInternet. <http://www.ntcresearch.org/pdf-rpts/AnRp02/F00-PH05-A2.pdf>

The following articles discuss braids with different mechanicalproperties, including mixing materials. “Analysis of three-dimensionaltextile preforms for multidirectional reinforcement of composites;”Guang-Wu Du, Tsu-Wei Chou and P. Popper; J. Mater. Sci. 26 (1991)3438-3448. Dunn, Matthew; Armstrong-Carroll, Eileen; Gowayed, Yasser;“Engineered Non-linear Elastic Bland Fabrics” [Retrived on Jun. 21,2006]. Retrieved from the Internet.<http://www.ntcresearch.org/pdf-rpts/Bref0601/F00-P05.pdf>.

The following article discusses the effect of braids on the mechanicalproperties of braided fabrics. There is considerable background onhybrid braids and their performance. Seneviratne, Waruna P. and Tomblin,John S.; “Design Of A Braided Composite Structure With A TaperedCross-Section;” National Institute for Aviation Research Wichita StateUniversity Wichita, Kans. 67260-0093 The Department Of Defense HandbookComposite Materials Handbook Volume 2, “Polymer Matrix CompositesMaterials Properties,” discusses braids in the context of compositematerials. [Retrived on Jun. 21, 2006]. Retrieved from the Internet.<http://www.lib.ucdavis.edu/dept/pse/resources/fulltext/HDBK17-2F.pdf>

DISCLOSURE OF INVENTION

A balloon for medical treatments such as percutaneous transluminalcoronary angioplasty (PTCA), delivery of a vascular stents or stentgrafts, employs reinforcement materials that are patterned so as topromote consistent, predictable, or tighter, folding of the balloon.

The invention provides a medical balloon whose walls have relativelystiff and relatively flexible regions to promote folding along theflexible regions. The variation in stiffness is achieved, according tothe different embodiments, by variably arranging composite elements on,or within, the wall of the balloon; by adding stiffening members to thewall at selected portions; by varying the properties of a fabric orbraid or other filamentous structure to define variable stiffness, andby other means.

According to an embodiment, the invention is a foldable compositeballoon with a wall. The wall has first and second filaments and firstand second wall portions. The wall has compression elements separatingthe first and second filaments in the first wall portions so that theydefine opposing tension elements running in a wind direction. Theopposing tension elements have a component in a specified direction andare separated by the at least one compression element resulting in thefirst portion being stiffer than the second portion, at least in thespecified direction, the first and second portions being arranged suchthat when the balloon is folded, the first portions resist bending morethan the second portions. This may be so the folds are generally alignedwith the second portions and it may help to ensure a neat andpredictable folding behavior when the balloon is collapsed. This in turncan help to ensure a compact configuration in tight areas.

Variations of this embodiment and others are possible. For example, thefirst and second filaments may be portions of elongate members that runcontinuously through the first portions and the second portions. Thefirst and second filaments may be braided to define at least a portionof a braid. The braid may include a triaxial portion having thirdfilaments running as a 0° braid yarn in the first and second portions,the third filaments in the first portions being thicker than the thirdfilaments in the second portion and the third filaments forming at leastpart of the at compression element. Note, the 0° yarn refers to yarnsrunning in a longitudinal direction, which is the direction along whichthe braid extends (or gets longer) as the braid is woven.

The first and second filaments may define at least a portion of a braidhaving, within the second portions, a greater number of crossingsbetween layer alternations than within the first portions. The first andsecond filaments may define at least a portion of a biaxial braidhaving, within the second portions, a greater number of crossingsbetween layer alternations than within the first portions.

The wall may be elongated such as to have a longitudinal axis and thesecond portion may be aligned with the axis or follow a helical patharound the longitudinal axis. The wall may include a matrix, such as apolymer matrix, and members embedded therein with the first and secondfilaments being embedded in the matrix and the members forming at leastportions of the compression elements.

The wall may include a matrix and flat members embedded therein, thefirst and second filaments being embedded in the matrix and the membersforming at least portions of the compression element.

According to an embodiment, the invention may also provide a foldablecomposite balloon with a wall of polymer matrix with first and secondfilaments attached to it. The wall may have first and second portions,the first and second filaments spaced apart by a portion of the polymermatrix in the first wall portions, such that they define opposingtension elements running in a wind direction having a component in aspecified direction and separated by the matrix portion. The spacing ofthe tension elements on opposite sides of the matrix portion is suchthat the matrix portion acts as a compression element and the result isthat the first portion is stiffer than the second portion, at least inthe specified direction. The first and second portions may be arrangedsuch that when the balloon is folded, the first portions resist bendingmore than the second portions. Or the second portions may be alignedwith folding lines of the balloon so the structure helps to promotefolding or creates a natural folding behavior.

This embodiment has variations as well, such as may include the firstand second filaments being portions of elongate members runningcontinuously through the first portions and the second portions. Thefirst and second filaments may be braided to form a braid. The first andsecond filaments may define a braid having, within the second portions,a greater number of crossings between layer alternations than within thefirst portions. The second portions may define folding contours and thealternations are staggered in the first region such that no consecutivetrains of side alternations occur that are parallel to the foldingcontours.

According to yet another embodiment, the invention is a foldablecomposite balloon with a body that has a polymer matrix and afilamentous structure attached thereto. The body may have first andsecond portions and folding lines with the filamentous structuredefining first and second portions, the folding lines lying within thesecond portions and the first portions lying between the secondportions. In one embodiment, the filamentous structure may be configuredto promote folding along the folding lines either by being configured tocause the body to be stiffer in the first regions, at least in adirection perpendicular to the folding line, than the second portions.In another embodiment, the filamentous structure may be configured togenerate a mechanical bias that favors folding along the folding linesas a result of being formed over a form with edges on it.

The filamentous structure may be configured to cause the body to bestiffer in the first regions, at least in a direction perpendicular tothe folding lines, than the second portions. The filamentous structuremay include a braid. The filamentous structure may have first and secondfilaments and a compression element, the first portions being stiffer,at least in a direction perpendicular to the folding lines, at least inpart as a result of the first and second filaments of the first portionsbeing arranged with the compression element between then, therebydefining opposing tension elements separated by the compression element.The braid may have layers with more layers in the first portions than inthe second portions such that the first portions are stiffer than thesecond portions.

The body may have a longitudinal axis and the folding lines are parallelto the longitudinal axis. The body may have a longitudinal axis and thefolding lines may wind helically around a longitudinal axis. The braidmay be triaxial or biaxial.

According to yet another embodiment, a foldable composite balloon isprovided which has a wall with a polymer matrix included elementsattached to, or within, the polymer matrix. The included elements arearranged to define first portions, and second portions of the wall suchthat the wall folds more readily in the first portions than the secondportions.

According to yet another embodiment, a foldable composite balloon isprovided with a wall having elongate reinforcement members, firstportions, and second portions, the stiffness of the first portions beinglower than the stiffness of the second portions. An arrangement of theelongate reinforcement members causes the wall to be stiffer in thesecond portions than in the first portions, whereby the balloon tends tofold along contours coinciding with the low stiffness portions.

According to an embodiment, the invention is a method for the treatmentof an infected area within a body. The method includes applying anelectrically conductive biocide composition to an infected area withinthe body that has been exposed during surgery, and applying an electricfield to the biocide composition by contacting a surface with thebiocide composition with an inflatable member having conductive surfaceof alternate polarity to generate an electric field. The electric fieldstrength and duration of application are sufficient to produce killingof microorganisms in the infected area. Preferably, the infected area iscomposed of a biofilm that is composed predominately of bacteria, yeastor fungus. Preferably, the biocide is an antibiotic selected from thefamily of antibiotics consisting of penicillins, cephalosporins,aminoglycosides, tetracyclines, sulfonamides, macrolide antibiotics andquinolones. Preferably, the electrically conductive biocide compositionis a buffered saline composition. Preferably, the biocide compositionincludes a thickener. Preferably, the electric field is substantiallyconstant. Preferably, the electrical field is a pulsed or alternatingelectric field. Preferably, the electric field strength is generated bycurrents having a value in the range from about 1 to about 200milliamps. Preferably, said electric field is applied to theelectrically conductive biocide composition for a period of time ofbetween about 1 minute to about 48 hours. Preferably, the biocide ispresent in the composition, in an amount which would be ineffective tocompletely kill the infected area if used in the absence of the electricfield.

In a particular variation of the above method embodiments, the method isperformed during the course of heart valve replacement surgery.Preferably, the biocide is an antibiotic, an anti-fungal agent, adisinfectant, a sterilant, other antiseptic agents, hexachlorophene,cationic bisiguanides, iodine, iodophores, para-chloro-meta-xylenol,triclosan, furan preparations, methenamine, aldehydes, or alcohols.Preferably, the cationic bisiguanides include chlorhexidene orcyclohexidene. Preferably, iodine include povidone-iodine. Preferably,iodophores include povidone-iodine. Preferably, furan preparationsinclude nitrofurantoin or nitrofurazone. Preferably, aldehydes is inglute form.

According to another embodiment, the invention is a medical balloon,comprising: a balloon body having an array of reinforcement fibersexposed on an external surface thereon; at least some of thereinforcement fibers being electrically conductive subsets of which areconnectable to a source of voltage such that an electric field can becontinuously generated on the surface of the body. Preferably, thefibers form a braided pattern. Preferably, the at least some of thereinforcement fibers are of metal. Preferably, the at least some of thereinforcement fibers are zero-angle fibers of a triaxial braid.

According to an embodiment, the invention may also provide a foldablecomposite balloon with a wall of polymer matrix with first and secondfilaments attached to it. The wall may have first and second portions,the first and second filaments spaced apart by one or more radio-opaqueelements in the first wall portions, such that the yarns overlying themdefine opposing tension elements running in a wind direction having acomponent in a specified direction and separated by the radio-opaqueportions. This allows the radio-opaque included elements to berelatively stiff without impeding (in fact promoting) the folding of theballoon. The spacing of the tension elements on opposite sides of thematrix portion is such that the included radio-opaque elements act ascompression elements and the result is that the first portion is stifferthan the second portion, at least in the specified direction. The firstand second portions may be arranged such that when the balloon isfolded, the first portions resist bending more than the second portions.Or the second portions may be aligned with folding lines of the balloonso the structure helps to promote folding or creates a natural foldingbehavior.

This embodiment has variations as well, such as may include the firstand second filaments being portions of elongate members runningcontinuously through the first portions and the second portions. Thefirst and second filaments may be braided to form a braid. The first andsecond filaments may define a braid having, within the second portions,a greater number of crossings between layer alternations than within thefirst portions. The second portions may define folding contours and thealternations are staggered in the first region such that no consecutivetrains of side alternations occur that are parallel to the foldingcontours.

In another embodiment, a foldable composite balloon has a braidedreinforcement structure defining a wall. The braided reinforcementpattern is such that the wall is stiffer at the first wall portions thanat the second wall portions. The first and second wall portions arearranged such that when the balloon is folded, the first portions resistbending more than the second portions. Preferably, at least the firstwall portions have a radio-opaque coating thereon. Alternatively, onlythe first wall portions have a radio-opaque coating thereon. In anotherpreferred embodiment, a radio-opaque material is integrated in the firstportions only.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate exemplary embodiments of theinvention, and, together with the general description given above andthe detailed description given below, serve to explain the features ofthe, invention.

FIG. 1 shows a reinforcement structure, such as a tube braid, that maybe used in a composite balloon, the reinforcement structure havingrelatively flexible portions or facets and relatively stiff portions orfacets.

FIGS. 2A and 2B are figurative illustrations of medical balloon fiberpreforms with longitudinal folding patterns, the first being straightand the second being helical.

FIG. 3 is a planar development of a portion of folded balloon wall lyingadjacent a catheter surface according to an embodiment of the invention.

FIG. 4A illustrates a braiding pattern that provides relatively stiffand relatively pliable portions.

FIGS. 4B and 4C are illustrations for helping to explain a feature ofthe braid pattern of FIG. 4A.

FIG. 5A illustrates a multi-balloon mandrel that may be used forbraiding or weaving multiple reinforcement structures for a balloon.

FIG. 5B illustrates a single-balloon mandrel that may be used forbraiding or weaving a reinforcement structure for a balloon.

FIG. 5C illustrates a base balloon over which a reinforcement structuremay be braided.

FIG. 6A is a flow diagram of a method for making a reinforced medicalballoon using a multi-balloon form.

FIG. 6B is a flow diagram of a method for making a reinforced medicalballoon using a single-balloon form.

FIG. 6C is a flow diagram of a method for making a reinforced medicalballoon using a liner balloon as a form.

FIG. 7 illustrates elements used in manufacturing a composite balloonaccording to an embodiment.

FIGS. 8A-8C illustrate steps in the manufacture of a composite balloonaccording to the embodiment of FIG. 7.

FIGS. 9A-9C illustrate a braiding pattern and yarn set that providesrelatively stiff and relatively pliable portions.

FIG. 10 illustrates a balloon embodiment in which reinforcement portionsare added in stages and sections.

FIG. 11 illustrates a reinforced balloon having a non-cylindrical shape.

FIG. 12 illustrates a cylindrical form with a non-circularcross-section.

FIG. 13 illustrates a molding apparatus for forming reinforcementstructures or combinations of balloons and reinforcement structures.

FIG. 14 illustrates another braiding pattern and structure that providesrelatively stiff and relatively pliable portions.

FIG. 15 illustrates yet another braiding pattern that providesrelatively stiff and relatively pliable portions.

FIG. 16 illustrates two alternative types of balloons inserted in anopening of a host.

FIGS. 17A and 17B illustrate embodiments of a medical balloonembodiments with conducting surfaces for use in biocidal procedures orother procedures where balloons having conductors are used.

FIG. 18 illustrates a fabric with conductive yarns.

FIG. 19 illustrates partly insulated conductive yarns for use withembodiments of the invention.

FIG. 20 illustrates a balloon with partly insulated conductive yarns.

MODE(S) FOR CARRYING OUT THE INVENTION

The various embodiments will be described in detail with reference tothe accompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

FIG. 1 shows a reinforcement structure, such as a tube braid, that maybe used in a composite balloon, the reinforcement structure havingrelatively flexible portions 106 or facets and relatively stiff portions102 or facets. A tubular braid 103 has stiff portions 102 that arerelatively stiff, or at least relatively stiff in the circumferentialdirection (i.e., the direction about the balloon axis). The tubularbraid 103 also has flexible portions 106 that are flexible relative tothe stiff portions 102, also, at least in the circumferential direction.

The tube braid 103 may be of strong filaments (not shown separately) ofany type, but in the present embodiments of folding medical balloons,they include relatively inelastic high strength synthetic fibers. Thefilaments may be a mix of different materials and cross-sectional shapesand different materials may be combined in various ways as discussedbelow. The braiding may be done using a variety of mechanisms which areknown in the art employing braid patterns and other structures describedherein. For example, the braiding of the tube braid 103 may be performedusing a programmable tube braider (not shown). Alternatively, the tubebraid 103 may be a portion of a non-cylindrical (three-dimensional)braid as illustrated in FIG. 2A with progressively tapering ends. Insuch a case, the filaments may be braided over a three-dimensional form(for example, as at 220 in FIG. 5B, described below) to create a desiredballoon shape.

The tube braid 103 may be embedded in, impregnated with, or otherwisecombined with a flexible material that can hold pressure and ensureagainst leakage to form a medical balloon. For example, the tube braidmay be glued over a base liner that has the shape of the desired kind ofballoon. A variety of known processes for forming composite structuresare suitable so the subject will not be expansively discussed here.

FIGS. 2A and 2B are figurative illustrations of medical balloon fiberpreforms with longitudinal folding patterns. In FIG. 2A, balloon preform105 has straight folding contours and in FIG. 2B, balloon preform 107has helical folding contours. The preforms 105 and 107, as describedbelow with reference to FIGS. 5A and 5B, may be braided over athree-dimensional form to achieve the illustrated shape. The differentportions with variegated flexibility, as identified above, are indicatedcollectively at 108 and 109. Note that a variety of other shapes may beused with the present inventive features and the shapes shown are merelyfor purposes of describing various folding features and structures.

FIG. 3 is a planar development of a portion of folded balloon wall lyingadjacent a catheter surface according to an embodiment of the invention.As will be understood by those of skill in the art, a very low profilecan be achieved in a medical balloon by configuring it to fold upondeflation. The folded shape shown in FIG. 3 shows a portion of the wallof a folded balloon 109. As indicated, the illustration is a planardevelopment and it is to be understood that the surface indicated at 104would wrap around the axis of the balloon which passes through the planeof the drawing, as would the overlying balloon wall 114 and folds. Forexample, the structure 111 may be a catheter with a circularcross-section. FIG. 3 shows how the relatively stiff portions 112 lierelatively flat while the folds coincide with the relatively flexibleportions 113. As a result, when the balloon 109 is deflated, the foldpattern may be more readily assumed by the balloon 109. Though notillustrated, a composite fiber reinforcement, such as the braiddiscussed above, is preferably incorporated within the wall 114 of theballoon 109.

The embodiments described above and below may be modified in such a waythat balloons may not be completely folded, in the sense that the wallis bent 180° and completely overlaps and contacts an adjacent portion,in order for the balloon to achieve a compact shape. That is, the wallmay simply be wrap or bend without making a fully 180° turn and/oradjacent portions may not lap once in the folded configuration. In suchembodiments, the portions of the wall that are stiffer will resistbending more than other portions. For example, in FIG. 3, portion 112resists bending more than portion 113. Note that since FIG. 3 shows aplanar development, portion 112 is generally wrapped around the axis ofthe balloon, even though it is represented as a flat portion. A balloonmay have a relaxed condition in the folded state (in fact this may bepreferred in some embodiments) in which case some parts of the balloonmay actually provide a negative resistance to bending to form the foldedconfiguration. So the term “resistance” here is used in a general sensethat covers zero, negative, and positive resistance. In other words, itis understood that the portions of the balloon that are bent the most,such as in folding, may achieve their most relaxed state in, forexample, a folded configuration, in which case, the balloon would notgenerate a positive resistance to folding because it tends to fold. Soin that case, the resistance at certain portions, for example foldlines, would be negative.

FIG. 4A illustrates a braiding pattern that provides relatively stiffand relatively flexible portions. FIG. 4A shows a triaxial braid fabric100 that may form part of a reinforcement structure for the wall of amedical balloon (not shown in the present drawing). In a flexible region110 and 112, which would coincide with regions 113 in FIG. 3, thebraiding pattern is a so-called diamond braid pattern with the yarnsalternating sides each time they cross a yarn. With the diamond braidpattern, longitudinal (longitudinal being defined as the direction ofthe long axis of the page which is also the long axis of the balloon)“seams” are formed where all the yarns cross sides along the samelongitudinal line. This makes the diamond pattern easier to bend becausethe seams are thin offer less resistance. In the stiff regions 115 (onlyone shown, but there would ordinarily be more) yarns generally crossmore than one 0° yarn before they cross sides. For example, in aHercules braid, a yarn crosses three other 0° yarns before crossingsides. In the illustrated braiding pattern for the stiff region 115, theyarns cross three other 0° yarns before crossing. The pattern ispreferably such that the crossing points lined up in the longitudinaldirection lines.

Refer now to FIGS. 4B and 4C, which illustrate how the braiding patternsof FIG. 4A of the flexible 110 and stiff 115 regions differ and how thedifferences contribute to relative stiffness. In FIG. 4B, the relativelyflexible diamond pattern is shown in a figurative cross-section. Theyarns 250, shown in section, represent longitudinal fibers of the axialbraid. Note that the figure is a figurative cross-section because,although the yarns 253 cross at a diagonal and, at any straightcross-section, continuous runs of crossing yarns could not be seen in areal cross-section, the illustration is functionally similar, as may beconfirmed by inspection. The seams, such as indicated at 252, whereyarns 253 cross, are arranged in successive ranks along the longitudinaldirection because yarns alternate at every crossing. In contrast, asshown in FIG. 4C, where yarns do not alternate at every crossing, astiffer structure is formed with crossing yarns 280 and 284 form tensionelements that, in combination with the embedded matrix (which resistcompression) define a stiff segment 288. The positions of the crossingpoints of other crossing yarns such as those shown crossing at 286, donot coincide in the lateral direction (i.e., the crossing lines are notaligned along longitudinal lines) so there no seam arises where thebraid would be easier to bend. Thus, for example, a stiff segment 290(shown with broken lines) which is longitudinally adjacent theforeground stiff segment 288, is offset in the lateral direction. Inthis way, the stiffness is extended laterally beyond the range of thestiff segment 288. This kind of stiff arrangement is illustrated in FIG.4A at 115.

FIG. 5A illustrates a multi-balloon form 215, or mandrel, that may beused for braiding (or weaving) multiple reinforcement structures for aballoon in a single braiding operation. A braid may begin at a topextension portion 216 and widen into a balloon portion 210 and then neckdown to a connecting section 217A. The braiding operation may continueover balloon sections 211 and connecting section 217 (arbitrary numberof them), and then over a final balloon section 212, and extensionsection 218, to form a structure (not shown) that may be cut intomultiple balloon preforms.

FIG. 5B illustrates a single-balloon form 220 with extension sections222 that may be used for braiding (or weaving) a single reinforcementstructure for a balloon. In both the 215 and 220 embodiments, the formmay be made of a disintegrating, or otherwise collapsible structure topermit it to be removed from the finished form 215, 220 to leave one ormore preforms. The cutting operation to divide the segments ofembodiment 215 may be done before or after the collapsing of the form215. FIG. 5C illustrates a base balloon over which a reinforcementstructure may be braided. The base balloon 240 with extensions 242 mayact as a liner portion of a finished balloon, functioning as a braidingform for fabrication of the braided structure and, optionally, thenremaining as part of the finished balloon. Preferably, the base balloon240 is fabricated of an inelastic material to facilitate its use as aform and base for braiding.

FIG. 6A is a flow diagram of an example of a method for making areinforced medical balloon using a multi-balloon form. In step S10, themultiple part form 215 is fabricated and in step S15, a braiding deviceis used to braid over the form 215 (FIG. 5A). In step S20, the resultingform and braided preform are then cut into segments to define theindividual preforms to be used in the separate balloons. In step S25,next, the underlying form is collapsed, for example by dissolving inacid or water, melting, reconfiguring, or performing some other step orsteps depending on the structure of the form. In step S30, a liner isinserted in each balloon preform and inflated. The liner may be formedsuch that it assumes the desired shape and size when inflated. In stepS35, in an embodiment, the liner is inflated with a pressurized fluidand the braided preform coated with a matrix which is cured in step S40and which serves to adhere the preform, the liner balloon, and thematrix together, forming an integral structure.

FIG. 6B is a flow diagram of a method for making a reinforced medicalballoon using a single-balloon form. In step S110, the form 215 isfabricated and in step S115, a braiding device is used to braid over theform 225 (FIG. 5B). In step S120, the underlying form is collapsed, forexample by dissolving in acid or water, melting, reconfiguring, orperforming some other step or steps depending on the structure of theform. In step S130, a liner is inserted in the balloon preform andinflated. The liner may be of a form and shape that requires moldingbefore adopting its final shape. A cylindrical mandrel may be insertedin step S135 to help seal and fill the balloon. In step S140, in thisembodiment, the liner is inflated with a pressurized fluid and then thebraided preform coated with a matrix that is cured in step S145 andwhich serves to adhere the preform, the liner balloon, and the matrixtogether, forming an integral structure.

FIG. 6C is a flow diagram of a method for making a reinforced medicalballoon using a liner balloon as a form. In step S210, the liner balloon220 (FIG. 5C) is fabricated and in step S215, a braiding device is usedto braid over the liner balloon 220 (FIG. 5C). In step S235, acylindrical mandrel may be inserted in the liner to help seal and fillthe balloon and the subassembly inserted in a mold. In step S240, inthis embodiment, the liner is inflated with a pressurized fluid and thesubassembly is heated until the braid is melted into the liner balloon,which thereby forms a matrix that seals the braided structure. Thematrix is then cooled in step S245 to form an integral structure.

In the foregoing embodiments, the method steps were deliberately variedto illustrate that there are multiple ways to form the balloon with anintegrated fiber braid reinforcement. For example in the methods ofFIGS. 6A and 6B, a curable coating is placed on a preform while in FIG.6C, a liner of thermoplastic is partially melted and cooled to form theballoon. It will be recognized that the various methods and features canbe altered and varied to form balloons and that no particular method isrequired to realized the benefits of the reinforcement structuredescribed in the instant application. For example, the fibers that arebraided may be coated, or the preform impregnated with finely dividedthermoplastic or adhesive with the liner balloon being of a high meltingtemperature than the molding temperature. Then in the method of FIG. 6C,the coating or impregnated material would then adhere the braid to theliner to form the balloon during thermal molding.

An alternative method of making a balloon without employing a mold is tobraid over a liner balloon using yarns that contain resin that flows ata lower temperature than the base material of the yarns of the baseballoon. For example high melting-temperature yarns may be coated withlow melting-temperature thermoplastic. After braiding over the baseballoon with the two-part yarns, the braid and base balloon may beheated to a temperature that causes the low melting-temperature resin toflow sealing any openings between the yarns. The base balloon materialand thickness may be chosen such that it may either be removed or leftin place depending on the properties of the material of the baseballoon.

FIG. 7 and FIGS. 8A, 8B, and 8C illustrate the manufacture of acomposite balloon according to an embodiment. A mandrel 302 withopenings 304 is inserted in a tube 314 of Polyethylene Terephthalate(PET), Nylon, or other suitable material, that will be molded to form aballoon liner. The mandrel 302 and tube 314 are inserted in a braidedpreform 308 and the substructure 332 then placed in a mold 310, 312,here illustrated as a two part mold. See FIG. 8A. Clamps 320 are placedover the ends of the mandrel 306 to seal the tube 314 and preform 308against the mandrel 306. The mold is then assembled (as indicated bybroken lines 322 or arrows 355) and compressed over the preform 308 (SeeFIG. 8B) and heated while air or other fluid is injected in the mandrel302 at an end opening 306. As a result the tube 314 balloon is softenedand expands under pressure. See FIG. 8C. After the tube 314, now aballoon 314A, has formed a composite balloon 314, the mold is cooled andthe composite balloon 314 is removed.

FIGS. 9A-9C illustrate a braiding pattern and yarn set that providesrelatively stiff and relatively pliable portions. The present embodimentis similar to that of FIGS. 4A-4C except that the 0° yarns 420 arelarger in cross-section than the other yarns within the stiff regions415. In the flexible regions 410 the yarns may be identical. The 0°yarns 420 in the present embodiment have the effect of separating thetension portions 420 further apart than the embodiment of FIGS. 4A-4Cthereby creating even greater stiffness.

In FIG. 9B, the relatively flexible diamond pattern is shown in afigurative cross-section with the 0° yarns 408, shown in section. Again,the seams, such as indicated at 423, where yarns 425 cross, arelongitudinally arranged because yarns 425 alternate at every crossing.In FIG. 9C, where yarns 425 do not alternate at every crossing, a lessflexible structure is formed with crossing yarns 420 forming tensionelements as described above with reference to FIG. 4C. Again,preferably, the braid pattern is such that stiff segments are offset andstaggered in a direction perpendicular to the longitudinal direction toprovide a cooperative continuous extension of the stiffness betweenstiff segments. Such a staggered arrangement is illustrated in FIG. 9Cby observing the positions of the alternation points of other crossingyarns 435, which do not coincide in the lateral direction.

Note that another embodiment of a braid may that employs a biaxial braidstructure may be created, which uses the same principle. In such anembodiment, no 0° yarns exist in the flexible regions 410 but 0°elements—not necessarily yarns—serve to separate the biaxial layers ofbiaxial yarns in stiff regions. In such an embodiment, the elements 420could be, for example, PET or Nylon filaments. In this case, the 0°elements may be of another material that helps to provide the resistanceto compression along with the material that forms the matrix.

FIG. 10 illustrates a balloon embodiment in which reinforcement portionsare added in stages and sections. Instead of braiding over a form tocreate a three-dimensional preform, the braiding structures describedherein may be braided as a cylindrical tube 515. The tube 515 may beslid over a balloon 505 and bonded or molded to it. In that case, theend portions may be formed by teasing the braid, folding it over(lapping it), cutting notches in it, or simply terminating it beforecompletely covering the ends. In addition, braid may be formed over theends as indicated at 510. For example, the tube 515 may be teased andthe fibers laid over the end (which is conical in the example) and ahelical wind may be wrapped over the conical ends. See U.S. Pat. No.6,746,425 for Medical Balloon; hereby incorporated by reference as iffully set forth herein; which describes a structure and method forwrapping a balloon with a helical wind. For example, the method whichmay involve the use of adhesive according to an embodiment in thereference, may be followed after the tube braid 515 is laid over a linerballoon and inflated to form the desired shape.

In variation on the embodiment of FIG. 10, 0° yarns may be extendedbeyond the end of the tube where the conical end portion is reached.These free longitudinal fibers may be adhesively bonded in place asdescribed in U.S. Pat. No. 6,746,425 and a helical wind added over thetop in the manner described in this patent. The free ends of the 0°yarns may be obtained by the braiding device or by cutting the orunraveling. Alternatively, the diagonal yarns may be included in thelongitudinal reinforcements over the conical portions.

FIG. 11 illustrates a reinforced balloon having a non-cylindrical shape.FIG. 11 is included to illustrate that the inventive reinforcementstructures are not limited to cylindrical balloons. For example, aballoon 524 that collapses using accordion folds 530 and 535 andinflates to an expanded shape such as a cylinder may be formed.

FIG. 12 shows a cylindrical form 550 with a non-circular cross-section.It may be beneficial to braid over such a non-cylindrical form, in somecases, to further promote folding, depending on the compatibility withyarn angles and other considerations. By braiding over such a form, thelengths of yarns are biased to favor the folded configuration, which isa property that is in addition to the variegated stiff and flexibleregions property discussed above. The cylinder 550 (note thattechnically, non-circular column shapes are still called “cylinders”)may have a helical wind to it if the fold lines are not longitudinal. Insome cases, it may be beneficial to use a stiffer braid throughout theentire braided structure (for example as described with reference toFIGS. 4A-4C and FIGS. 9A-9C), which would result in shorter tensionmembers 284 and 420 adjacent the sharp bends 552 (typ.) than in thelayer remote from it. Thus, such a structure would retain a bias towardits folded configuration as if the braid were “molded” or annealed to bein its most relaxed state when folded. FIG. 13 illustrates a moldingapparatus for forming reinforcement structures or combinations ofballoons and reinforcement structures. The mold includes a centralportion 582 and a wing portions 584. Using such a structure, a ballooncan have a folded shape bias molded into the matrix as well as theproperties of additional flexibility in the folded portions, and/orfolded bias, in the composite substructure (e.g., the braid).

FIG. 14 illustrates another braiding pattern and structure that providesrelatively stiff and relatively pliable portions. Here, a stiff region570 has a spacer 576 over which the braid is woven. The spacer 576 maybe held as a 0° yarn and braiding may be performed around it. The layersof the flexible regions 572 are adjacent to allow them to be moreflexible. The separated layers of the stiff region 570 contributestiffness in a manner similar to that described with reference to FIGS.4B-4C and FIGS. 9B-9C. That is the upper layer and lower layers act astension elements over an incompressible core in the form of the spacer576. Note that the layers in the flexible regions 574 may be woven intoa single fabric using three-dimensional braiding equipment. See forexample, three dimensional braiding as described in U.S. Pat. Nos.5,357,839; 5,772,848; and 6,090,137, hereby incorporated by reference asif fully set forth herein.

FIG. 15 illustrates yet another braiding pattern that providesrelatively stiff and relatively pliable portions. The stiff portions 592are formed by overbraiding (braiding on top of a braid to form anadditional layer) with an overbraided layer 586 in only the regions 592that are to be stiffened. This may be done using less expensivetwo-dimensional braiding equipment. The braid pattern may include yarns590 that connect the overbraided layers 586. The thin region is definedmostly by the lower layer 588. In another embodiment, a spacer such as576 in FIG. 14 is included between the layers in the stiff regions. Notein this embodiment, a spacer may be included by an intermediatelamination or coating step in which the spacer is placed on a balloonrather than being positioned and included as part of a braid preform.

In a preferred embodiment, the stiff portions 592 can be made of aradio-opaque material to enhance visualization of the balloon in situ.Alternatively, the stiff portions 592 can have a radio-opaque materialintegrated into them or coated on them to make them radio-opaque. Thismay allow the use of radio-opaque materials which might be tooinflexible or otherwise difficult to integrate in a medical balloon.

In any of the embodiments described herein, the balloon may be coated orimpregnated with a radio-opaque material or have the radio-opaquematerial otherwise integrated into them, such as by the braiding processas discussed in the instant specification. Such radio-opaque materialscan be restricted the relatively flat (non-folding) portions of theballoon wall which may permit the use of materials that cannot tolerateas high a degree of strain if used in portions that are folded tightly.

Examples of materials that may be used for the matrix and or liner ofthe above embodiments include polycaprolactam, polyesters, polyethers,polyamides, polyurethanes, polyimides, ABS copolymers,polyester/polyether block copolymers, ionomer resins, liquid crystalpolymers, and rigid rod polymers.

Applications of the medical balloon embodiments include vasculardilatation, stent delivery, drug delivery, delivery and operation ofsensors and surgical devices such as blades, and the like. Exemplarydesign parameters of balloons within the scope of the invention includeballoons with burst pressures of 100 psi or more.

Note that although many of the examples discussed and illustrated abovewere based on triaxial braid structures, biaxial the benefits of theinventive embodiments may be applied to other braid patterns. Suchpatterns include multilayer and so-called thick braids orthree-dimensional braids.

Also note that there are types of braiding technology that allow a highdegree of flexibility and control for forming braids. Suitabletechnology and techniques as may be combined with the teachings of thisdisclosure may be found in: U.S. Pat. Nos. 5,085,252; 5,465,760;6,129,122; 6,315,007; and 6,439,096, which are hereby incorporated byreference as if fully set forth herein.

Also note that although the embodiments are described in terms of braidsas a base technology, it possible to achieve the same benefits using aweaving or combination weaving and braiding technology. In such casesthe stiffening properties may be derive from warp and/or weft yarns in afabric weave. Moreover, current technologies for knitting, weaving, andbraiding have blurred the boundaries of these categories so the termsshould not be taken as limiting.

In the instant disclosure, the words “yarn” and “fiber” are usedinterchangeably. The term “yarn” is commonly used in the field ofbraiding. The term is not intended to limit the material, composition,or structure of the fiber material that is used in any of theabove-described embodiments. In addition, the structures disclosed maybe created in various ways including mechanisms that do not includebraiding. Thus, even where the term “yarn” is used and/or where braidingis described as a preferred means of forming a structure, the uses arenot necessarily intended to limit the structures described to onesformed by braiding.

A variety of materials can be used for the fibers/yarns. Examplesinclude, but are not limited to, high strength inelastic fibers such asKevlar, Vectran, Spectra, Dacron, Dyneema, Teflon (PBT), Zylon (PBO),Polyimide (PIM), ultra high molecular weight polyethylene, and the like.In addition, fibers/yarns may have non-circular cross-sections. Forexample, flat fibers/yarns may provide superior amenability to folding.

In any of the above embodiments, the balloon or the braid pre-form canbe coated with suitable materials (paint) to render the resultingmedical balloon radio-opaque. Suitable coatings are known, for example,as discussed in U.S. Pat. No. 6,599,448, hereby incorporated byreference as if fully set forth herein. In addition, some or all of theyarns or fibers employed may be radio-opaque to enhance theradio-opacity of the resulting balloon. This can be performed, forexample, by applying a coating to the balloon, or fibers using vapordeposition or electro-energy deposition, for example, a metal coatingsuch as tantalum or other materials such as barium sulfate. Also, ametallic layer can be used in treatment such as to provide a means forcreating an electric field inside the body for sterilizing a site.Examples of such applications and biocides are described in U.S. Pat.No. 6,258,249 (Charles Lee Simpson for “Sterilization of surgicalsites”) which is incorporated by reference as fully set forth herein.

Referring now to FIG. 16, a medical balloon 601 may be of any suitablestructure including monolithic polymer, composite with fibers, includingbraided fibers, laminates, or any other suitable structure. The medicalballoon 601 has conductive surfaces (not shown in this view) on itsexternal surfaces to allow the generation of an electric field forperforming the biocidal function described in U.S. Pat. No. 6,258,249patent incorporated by reference above. In the example shown, theballoon 601 is inserted between two surfaces 606 and 608 of a bodycavity, a surgical or traumatic wound in a host 604. The balloon 601 maybe coated with a biocide as described in U.S. Pat. No. 6,258,249 patentand the conductive surfaces connected to a source of voltage(alternating or direct) to destroy biofilm or other susceptibleinfectious material. The balloon 601 may be inserted and moved around,with an internal pressure that allows the balloon 6021 to conform to thesurfaces 606 and 608. A cylindrical balloon 614 may be inserted in alumen structure 616 of the host 604 to perform the same function. Forexample, the lumen could be a blood vessel, a urethra, a duct, or anyother cylindrical cavity or conduit. The internal space 602, 610 ofeither balloon 601, 614 can be filled with any suitable material suchas, for example, saline.

Further details of the balloons of FIG. 16 are shown in FIGS. 17A, 17B,as well as FIGS. 18 through 20, according to various alternativeembodiments. Referring now to FIGS. 17A and 17B, the surface of balloons630 and 660 are striped with first and second conductive strips 634 and636 for balloon 630 and 664 and 666 for balloon 660. The strips arelabeled 1 and 2 to indicate which of two poles of a voltage source (notshown) they are connected to. The strips 634 and 638 or 664 and 666 canbe painted, sputtered, laminated, or otherwise deposited on the balloonin any suitable manner.

In an alternative embodiment, the strips 634 and 638 or 664 and 666 maybe realized by employing conductive yarns in a braid pattern whosesurface is exposed on the balloon 630, 660. The surface may be exposedby creating a braided preform in which parallel sets of conductive yarnsare used. Then a base balloon with an adhesive, for example, a thermallyactivated adhesive or thermopolymer layer, may be inflated within thepre-form. The adhesive may not be required depending on the requirementsof the application, but the result is preferably one in which theconductive yarns are exposed on the surface of the balloon to create thepatterns shown in FIGS. 17A and 17B. The conductive surfaces of theballoon 630 and 660 may be carried to terminals 638, 640 or 668, 670,respectively, for connection to the voltage source.

FIG. 18 shows an example of parallel conductive yarns, in this case, thelongitudinal yarns 704 are held in position and maintained parallel bythe triaxial braiding pattern of the fabric 706. The conductive yarns704 may be interspersed with non-conductive yarns. In alternativeembodiments, some or all of the diagonal yarns 703 may be madeconductive. The polarity may alternate as every N yarns in any desiredmanner to achieve a desired spacing of the oppositely polarized yarns.Note that the conductive yarns may be of metal, carbon-impregnatedfiber, carbon composite, or any suitable material. Note also that abraid is not required to employ conductive fibers in this manner. Forexample yarns can be laid into a mold and a balloon molded into it asdescribed in U.S. Pat. No. 6,746,425, hereby incorporated by referenceas if fully set forth herein. Any adhesive or matrix remaining on thesurface can be polished off to expose the conductive yarns.

Referring to FIGS. 19 and 20, the conductive yarns can be provided withinsulation in parts to provide that the conductors are exposed only atdesired locations on a balloon. For example, conductors 752 and 754(which indicate sets of alternating polarity), in the array 706,depicted in FIG. 19, are exposed only in a region 756 (or 786 in theFIG. 19 embodiment). A region 757 exposes the conductors 752 and 754 ata terminal region 757 for connection to a source. The conductors 752 ofone polarity may be exposed by lack of insulation in a different axialposition than the conductors 754 of the other polarity to facilitateconnection to voltage sources as illustrated in FIG. 20. Here, region782 is a region in which the yarns of one polarity are exposed and theyarns of the other polarity are insulated. Region 780 is a region inwhich the yarns of the other polarity are exposed and the yarns of theone polarity are insulated. In this way conductive take-offs 781 and783, can be soldered or otherwise electrically connected to theconductive yarns without causing shorting.

While the present invention has been disclosed with reference to certainpreferred embodiments, numerous modifications, alterations, and changesto the described embodiments are possible without departing from thesphere and scope of the present invention, which is described, by way ofexample, in the appended numbered paragraphs below. Accordingly, it isintended that the present invention not be limited to the describedembodiments, but that it have the full scope defined by the language ofat least the following claims and equivalents thereof.

1. A foldable composite balloon, comprising: a wall having elongatereinforcement members, first portions, and second portions, saidelongate reinforcement members running through both the first portionsand the second portions in a braided or woven pattern; an arrangement ofthe elongate reinforcement members being such that the wall is stifferin the second portions than in the first portions, whereby the balloontends to fold along contours coinciding with the low stiffness portions.2. The balloon of claim 1, wherein at least the first wall portions havea radio-opaque coating thereon.
 3. The balloon of claim 1, wherein onlythe first wall portions have a radio-opaque coating thereon.
 4. Theballoon of claim 1, wherein at least the first wall portions have aradio-opaque material integrated therein.
 5. The balloon of claim 1,wherein only the first wall portions have a radio-opaque materialintegrated therein.
 6. A composite balloon comprising: a balloon wallcomprising a first set of longitudinal fibers running along alongitudinal length of the balloon wall; the balloon wall furthercomprising a second set of braided fibers forming a braid pattern arounda circumference of the balloon wall; wherein the braided fibers areinterlaced around the longitudinal fibers.
 7. The composite balloon ofclaim 6, wherein the balloon comprises a radial direction, and whereineach of the braided fibers passes radially inward from at least a firstof the longitudinal fibers and radially outward from at least a secondof the longitudinal fibers.
 8. The composite balloon of claim 6, whereinthe balloon wall comprises a central barrel section surrounded bycone-shaped end sections.